2 Answers
2

This is most certainly possible in Pixelmator by using a brush in the form of a star. You can easily create one yourself straight in Pixelmator or you search on the net for an image of a star. Make sure the area around the star is transparent then you can save the star as a png-file and drag and drop that file onto the brushes palette. Now with the brush tool you can click on each blurry christmas light and cover it with the star. Try different blending modes for the brush. It could be you could get better results then.

It is also possible to create a bokeh effect in Pixelmator. The guys at http://pixelmatortutorials.net have had a tutorial about this some time ago. The bokeh effect is done by applying one of the standard filters in Pixelmator.

This is great. Can you show us an example of it done after the fact compared with one done with a paper cutout in the shot? I find it hard to believe the effect will be the same but seeing is believing.
–
RichardDec 23 '11 at 19:03

I searched through the video tutorials for creating a bokeh effect but could not find it. I'm sure it must be there if you've seen it but maybe you can point me to it. Same with the star cutout. I'd love to see how this is done after the fact and compare it with effects done in the camera.
–
RichardDec 23 '11 at 19:11

Thanks for your answer. It is now marked as the official answer.
–
Johan KarlssonDec 28 '11 at 8:39

I realize that it is better to create this effect while shooting, for example using a filter. However that is not the case. So I need a way to fix this on my computer.
–
Johan KarlssonDec 22 '11 at 15:46

... and I'm saying you cannot fix this after the fact. You can attempt to edit the round christmas light bokeh with pixelmater or photoshop but I doubt you'll be able to achieve your desired effect after the fact. Let me know if you can, I'll be interested to see how. It's so easy to make a paper cutout and redo the shoot I think that's probably the better solution for you.
–
RichardDec 22 '11 at 23:29

I guess that you are right. But I thought it would be worth a try to ask for it.
–
Johan KarlssonDec 23 '11 at 9:01